@robertn It's unusual that this is ongoing and you're still unable to send and receive emails over 4G. Have you tried turning your 4G off and sending or receiving emails via your 3G connection? This will help us to identify if this is a standalone 4G issue or the mobile network as a whole.

As everything seems to be working with everything else whilst connected to 4G, it's still worth checking some of the basic internet settings.

Have you tried setting up a basic (non company) email account, such as hotmail? This will help us to understand if it's all emails, or only certain email accounts that are affected.

It sounds as though the service provider may be restricting mobile connections. This is usually more likely to affect outgoing than incoming, but I think your best recourse is to contact the service and ask them whether this is the case. As other services are OK, it would appear not to be a Vodafone/4G issue. It would be worth trying what Loz suggested, though, just to rule out something very weird.

I did ask them and they were adamant that this was not the case. As I've said before it used to work but stopped and when I tried a Vodafone PAYG SIM in the Motorola One it worked straight away. I will try Loz suggestion and see if that works.

There was an assumption in an earlier reply that other data connections (ie web & apps) were working OK, but I can't see that confirmed. Is it? If so, then this appears to be confined to email and this device. The only other suggestion I can come up with would be to refresh the APN by texting WEB to 40127 (although a fault with that ought to affect all data connections).

I ahve been having the exact problem, after phones calls to VF and resetting Iphone 7 wiping reinstalling I found one thing thats seems to work - Switch OFF 4G and phone reverts to 3G and voila all emails send and recievce without any changes or fuss - this to me seems to be a 4G issue and I think its getting incorrect IP addresses that are either being blocked or are not reconised by the emial servers. hope this helps.

Hi, make sure all outgoing email details are completed username - email address and password, also confirm the port numbers are correct pop is normally 25 or 487 I think I found if all details are not complete 3and 4 G networks don’t work but on WiFi will, it’s an odd thing.

Thanks to all for the help. The current state of play is, with my Motorola One over WiFi & 4G I can do everything I try, ie browse websites, receive gmail, outlook etc. Using K9 mail with WiFi I can send and recieve emails via the POP3 and SMTP accounts. Over 4G I can send via SMTP but POP3 does not receive..

I have just tried on a PAYG O2 Moto G4 with K9 mail using the same configuration and this works ok over 4G send and receive. I don't know what this proves, (if anything). FWIW On the Motorola One if I try to alter the POP3 settings on K9 mail it will not connect over 4G.

You mentioned that you’ve tried a Vodafone Pay as you go SIM in the Motorola One and this worked. Do you usually use a Pay monthly SIM? If so, have you tried putting your Pay monthly SIM into the Motorola One (instead of the G5)? Please try this and let me know if this make any difference.

Jenny. Thanks for the suggestion. I was waiing for a new PAYG SIM for Vodafone to try. I usually use a "Pay Monthly SIM" for everything. I put the PAYG Vodafone SIM in this afternoon and all works perfectly. I can send & receive emails on K-9 & BlueMail, browse the web and use Gmail etc. Any ideas on why this should be?

Thanks for getting back to us. I can see you mentioned you've tried the Pay as you go SIM in the Motorola Oneand everything worked perfectly.Have you been able to try your Pay monthly SIM in the Motorola One instead of the G5? This will help us to pinpoint any possible issues with the Pay monthly SIM or the phone.

Colleen. Thanks for the reply. Yes it is my Pay Monthly SIM in the Motorola One that has this fault. Sorry I didn't make that clear. I no longer have the Moto G5 but the problem was with that phone as well..

Sorry for the confusion @robertn This is an unusual one so I've done a bit of digging. As the issue has affected multiple phones, I don't believe the problem would be with either the phones or your SIM. It's possible that the issue may be due to the third party email apps you're using. The Google Play store suggests that if you're experiencing any faults with the K-9 app, you can raise them here. This will give them the chance to resolve everything for you.Please give this a try and let us know how you get on 😊

Thanks for the reply. I don't think the problem is with the email apps. I have used K-9, Blue mail and Aqua Mail. All work ok with wireless and with the PAYG SIM but fail to receive when used over 4G. The only difference in settings being changing over to PAYG WAP. As I've said before it has worked previously for some years.

You mentioned previously that Gmail and Outlook both work with no problems over 4G. As other email apps aren’t having any issues and everything else is working with both Wi-Fi and 4G, this really does point towards the problems being specifically with the email apps you’re using.

This is something we don’t have any control over and it may be worth contacting the email provider directly, to see if there have been any changes made at their end (security setup/requirements etc) that may have caused this.

I’m sorry this isn’t the answer you were looking for – I’m unable to think of any further troubleshooting steps or settings that can be checked by us.